Real Estate (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Real Estate Owned, Disclosure of Detailed Components [Abstract]
Land	$ 1,754,708		$ 1,754,708		$ 1,767,029
Building and tenant improvements	7,853,233		7,853,233		7,741,607
Lease intangibles	579,361		579,361		614,964
Real estate, gross	10,187,302		10,187,302		10,123,600
Accumulated depreciation and amortization	(2,623,144)		(2,623,144)		(2,481,250)
Total	7,564,158		7,564,158		7,642,350
Accrued capital expenditures and tenant improvements			32,200		46,900
Accumulated amortization	515,600		515,600		533,100
Intangible liabilities relating to below-market leases	354,600		354,600		372,100
Accumulated amortization on below-market leases	263,700		263,700		267,100
Below-market lease intangible amortization	4,100	$ 4,500	12,400	$ 14,100
Amortization of intangible assets	4,500	$ 6,700	14,800	$ 19,500
Leases, acquired-in-place
Real Estate Owned, Disclosure of Detailed Components [Abstract]
In-place lease value	521,700		521,700		554,900
In-place lease amortization expense
2020 (remaining three months)	3,946		3,946
2021	12,870		12,870
2022	9,003		9,003
2023	6,554		6,554
2024	4,887		4,887
Above market leases
Real Estate Owned, Disclosure of Detailed Components [Abstract]
Above market leases	57,700		57,700		$ 60,100
Below-market lease accretion (income), net of above-market lease amortization expense
Below-market lease accretion (income), net of above-market lease amortization expense
2020 (remaining three months)	(3,144)		(3,144)
2021	(11,290)		(11,290)
2022	(9,337)		(9,337)
2023	(8,114)		(8,114)
2024	$ (7,601)		$ (7,601)